Accounting for Selection Bias and Redshift Evolution in GRB Radio Afterglow Data

TL;DR

This paper applies the Efron-Petrosian method to correct for selection bias and redshift evolution in GRB radio afterglow data, revealing intrinsic correlations and emphasizing the importance of bias correction for accurate astrophysical and cosmological analyses.

Contribution

It introduces a correction methodology for GRB variables using the Efron-Petrosian method, accounting for selection effects and redshift evolution in radio afterglow data.

Findings

Strong redshift evolution observed in radio luminosity and other variables.

Bias correction aligns GRB data with intrinsic properties across wavelengths.

Highlighting the necessity of bias correction for reliable cosmological use.

Abstract

Gamma-ray Bursts (GRBs) are highly energetic events that can be observed at extremely high redshift. However, inherent bias in GRB data due to selection effects and redshift evolution can significantly skew any subsequent analysis. We correct for important variables related to the GRB emission, such as the burst duration, $T_{90}^*$, the prompt isotropic energy, $E_{\rm iso}$, the rest-frame end time of the plateau emission, $T_{\rm a, radio}^*$, and its correspondent luminosity $L_{\rm a, radio}$, for radio afterglow. In particular, we use the Efron-Petrosian method presented in 1992 for the correction of our variables of interest. Specifically, we correct $E_{\rm iso}$ and $T_{90}^*$ for 80 GRBs, and $L_{\rm a, radio}$ and $T_{\rm a, radio}^*$ for a subsample of 18 GRBs that present a plateau-like flattening in their light curve. Upon application of this method, we find strong evolution with redshift in most variables, particularly in $L_{\rm a, radio}$, with values similar to those found in past and current literature in radio, X-ray and optical wavelengths, indicating that these variables are susceptible to observational bias. This analysis emphasizes the necessity of correcting observational data for evolutionary effects to obtain the intrinsic behavior of correlations to use them as discriminators among the most plausible theoretical models and as reliable cosmological tools.